Back wheel wobbling a bit? Bike shop? Pah!

No, far better to just undo your v-brakes, even take the pads out if you like, and then just let the wheel wobble free. Leave it until it rubs on the frame, perhaps. The rubbing noise can join the creaking from your BB and the grinding from your chain in some sort of Stockhausen-esque cacophony symphony of maintenance discord.